The invention relates to a device for machine knitting with at least one continuous yarn, in which the yarn, by means of the hook part of a knitting needle, is passed in a loop through the previously formed loop and forms a new loop, in which the knitting needle, below the needle hook, has a slot into which a downward-oriented transfer hook movable in the vertical direction can be introduced.
In all previously employed methods for loop formation, the last-formed loop is held by a hook, embodied as the head of the needle, which then as the needle is advanced is brought into a shunt position. From there, via a yarn newly caught in the needle hook, upon retraction of the needle by means of shunt repositioning, it is brought over the closed hook and after the new loop has been drawn through the old loop is cast off over the latter. Hence the needle hook has two tasks: to hold the last loop and thus the knitted good formed until that point and to catch a new yarn and fashion it into a loop.
The use of the device for loop formation depends decisively on being able to assure certainty when the transfer hook plunges into the slot of the needle cheek. It is already an advantage that the needle and the transfer hook have the same shank thickness, which for relatively coarse pitches provides adequate certainty that the transfer hook, in its reverse motion, will enter the needle cheek. With very fine pitches, the lateral play in the needle channels and deviations in the lateral straightness of the loop formation elements can cause the transfer hook to strike the side wall of the needle slot instead of getting into the slot. In warp knitting machines this danger is even greater, since the loop formation takes place at a greater distance above the upper edge of the bar, so deviations in the lateral straightness can have an exaggerated effect.
From German Published, Examined Patent Application DE-AS 26 47 185, a method for machine knitting with at least one continuous yarn is known in which the yarn is passed in a loop through the previously formed loop and forms a new loop that is then held tightly, essentially in the same plane as the previously formed loop, until the next yarn caught, at the onset of loop formation, reaches the region of loop formation.
From German Patent Disclosure DE 29 50 147 A1, a knitting machine that has needles without latches is also known, in which perpendicular to the needle cylinder axis, relatively long shank parts are disposed as selector elements in radial slots and can be moved transversely and pivotably to the needle by control devices.
From German Patent DE 29 09 963 C2, a method and a device for machine knitting are known in which the needles, on the front side of the needle shank, each have an auxiliary part, which is guided like the needle and is controlled in its longitudinal direction and which widens the loop to be cast off and holds it until the new loop is drawn through.
In all the conventional knitting methods, a widening process is necessary, which is accomplished upon advancement of the needle by the rise from the neck to the cheek. The needle cheek at the same time serves to support the latch, or in compound needles, it serves to receive and guide the closing element.
In the known latch needle, the yarn must overcome a plurality of sliding resistances. First because of the rise of the needle cheek, then along the latch that is open at the rear, and finally upon retraction of the needle the rise to the hook and the widening via the latch spoon. In the compound needle it is problematic that the closing element has to disappear in the needle cheek, yet in the closing position is supposed to cover the hook. This puts limits on precision embodiments.